BACKGROUND:Pulsed field ablation (PFA) of atrial fibrillation has been rapidly adopted, partly because of safety expectations compared with thermal ablation. Comparative safety data between the 2 modalities remain limited. METHODS:We conducted a prospective registry analyzing consecutive atrial fibrillation ablations at a high-volume US academic center between 2022 and 2026. The primary end point was stroke or transient ischemic attack (TIA) within 30 days, independently adjudicated by blinded neurologists. Secondary end points included death and other procedural complications. Propensity score methods with inverse probability of treatment weighting were used to balance differences in patient characteristics. Differences in the procedural workflow of PFA versus radiofrequency ablation (RFA) were evaluated with exploratory mediation analyses. RESULTS:A total of 4221 ablation procedures (2077 RFA and 2144 PFA: 68.7% Farawave, 23.3% Sphere 9, 6.9% Varipulse, 0.7% PulseSelect) was performed by 12 operators. Patients receiving PFA and RFA had similar baseline characteristics (mean age, 67 years; 31% female; 47% persistent atrial fibrillation; 7% previous stroke/TIA), which were balanced after inverse probability of treatment weighting. Compared with RFA, PFA procedures were shorter (108 versus 144 minutes) and included more frequent posterior wall isolation (57% versus 31%). The 30-day rate of stroke/TIA was significantly higher for PFA cases (10 events; 0.47%) compared with RFA (2 events; 0.10%) in both unweighted and propensity score-weighted analyses (weighted risk difference, 0.36% [95% CI, 0.03%-0.70%]; P=0.03). Stroke/TIA events were evenly distributed throughout the study period with no clustering around the time of PFA adoption or operators (with no operator associated with ≥2 events). Exploratory mediation models were limited by the low event rates and did not identify more extensive ablation as an independent risk factor for stroke. Weighted rates of other procedural complications were low (<1%) and similar between PFA and RFA groups. CONCLUSIONS:In a high-volume, single-center registry with high clinical granularity and systematic patient follow-up, PFA was associated with a significantly higher risk of stroke/TIA at 30 days compared with RFA. These results call for enhanced postmarket surveillance and dedicated prospective evaluation as the PFA procedural volume continues to exponentially increase.

BACKGROUND AND AIMS:Pulsed field ablation (PFA) has emerged as a non-thermal alternative for pulmonary vein isolation (PVI), offering shorter procedural times and a favorable safety profile for atrial fibrillation (AF) ablation. However, large-scale data evaluating its efficacy in patients with persistent AF remain limited. Our objective was to perform a systematic review and meta-analysis evaluating 12-month atrial arrhythmia recurrence following PFA in patients with persistent AF. METHODS:A systematic search of MEDLINE, Embase, Scopus, LILACS, and Cochrane databases was performed. Studies including patients with persistent AF undergoing first-time PVI with PFA and reporting 12-month arrhythmia-free survival were included. When available, outcomes were compared with thermal ablation using time-to-event analyses. Random-effects models were used. Exploratory meta-regression analyses were conducted to assess potential sources of heterogeneity. RESULTS:Among 1699 screened studies, 26 met the inclusion criteria, comprising 3744 patients with persistent AF treated with PFA. The pooled 12-month freedom from atrial arrhythmia recurrence was 72.3% (95% CI, 69.0-75.5), with substantial heterogeneity (I² = 74.4%). Eight studies (31%) included a thermal comparator; pooled time-to-event analysis demonstrated no significant difference between PFA and thermal ablation (HR, 0.91 [95% CI, 0.78-1.07]). Exploratory meta-regression did not identify significant effect modification by baseline characteristics, lesion-set strategy, rhythm monitoring intensity, or year of publication. Ablation-related adverse events occurred in < 1% of cases for both energy sources. CONCLUSION:In patients with persistent AF, PFA is associated with a high arrhythmia-free survival at 12 months and low rates of ablation-related adverse events. Comparative findings versus thermal ablation should be considered exploratory and interpreted cautiously, given the limited and heterogeneous comparator data.

BACKGROUND:Conduction disturbances requiring permanent pacing frequently complicate transcatheter aortic valve replacement (TAVR). The understanding of mechanisms causing conduction block is incomplete. OBJECTIVE:This study aimed to characterize the acute and delayed electrophysiological (EP) effects of TAVR on the atrioventricular (AV) conduction system. METHODS:We conducted a single-center prospective cohort study of 409 patients undergoing TAVR. All patients underwent 12-lead electrocardiography and EP study (EPS) immediately before and after valve implantation, with continuous electrocardiography and EP monitoring during the TAVR. 7 patients with AV block underwent repeat EPS 1-12 days after TAVR. RESULTS:TAVR was associated with significant prolongation of sinus cycle length, atrio-His and His-ventricular (HV) intervals, and Wenckebach cycle length (all P < .0001). Transient AV-nodal conduction block occurred in 8% of patients with intraprocedural AV block and 12% with postprocedural block. Infranodal block occurred in 57 patients, but resolved in 41 by the end of the procedure. Marked HV interval prolongation (>100 ms) without conduction block occurred in 6.4% of patients during TAVR. Intra-His Wenckebach-type block occurred in 9 patients. In 7 patients with follow-up EPS 1-12 days after TAVR, improvement or resolution of AV-nodal and infranodal conduction abnormalities was seen in all. CONCLUSION:Peri-TAVR conduction disturbances may involve both the AV node and His bundle. The usual parameters indicating need for permanent pacing (marked HV prolongation) do not apply to TAVR patients. Distinguishing nodal from infranodal involvement can inform prognosis, anticipated recovery, and pacemaker decision making, particularly given that many conduction abnormalities resolved within 2-4 weeks, supporting a refined post-TAVR risk stratification strategy. CLINICALTRIALS: GOV IDENTIFIER:NCT04982406.

Background: Pulsed field ablation (PFA), a new catheter-based, non-thermal ablation technique, enhances the safety and efficacy of catheter ablation of atrial fibrillation (AF) compared to conventional thermal methods. While widely adopted in Europe and the United States, its application in Brazil is recent and remains undocumented. Objective: This study reports the initial multicenter Brazilian experience with the pulse field ablation to treat patients with AF, emphasizing its rapid adoption and short learning curve. Methods: A retrospective analysis of 394 consecutive procedures, performed by 60 operators across multiple Brazilian centers, was conducted. Data encompassed patient demographics, procedural metrics, imaging modalities, and ablation outcomes. A sub-analysis compared high-volume operators (n=139 procedures) with others (n=255). All statistical tests were two-tailed, with a p-value threshold of <0.05 for statistical significance. Results: Paroxysmal AF was predominant (62%), with pulmonary vein isolation (PVI) only as the primary lesion set in 54%. General anesthesia was near-universal (98%), and no major complications occurred. High-volume centers had significantly shorter procedure and ablation times (82 +/- 27 vs. 131 +/- 76 minutes; p<0.001 and 33 +/- 14 vs. 50 +/- 33 minutes; p<0.001, respectively), alongside fewer additional lesions after remapping (7% vs. 30%; p<0.001), suggesting a rapid learning curve. Conclusion: Pulsed field ablation demonstrates high acute efficacy, safety, and ease of adoption in Brazil, with a notably short learning curve, as evidenced by the efficiency of high-volume operators. Long-term outcome studies are warranted.

BACKGROUND:Early recurrence of atrial tachyarrhythmias (ERAT) is common after pulmonary vein isolation (PVI) and is traditionally attributed to transient post-procedural inflammation. With the introduction of pulsed field ablation (PFA), the incidence and prognostic significance of ERAT compared with thermal ablation remains unknown. OBJECTIVE:The study aimed to compare the incidence of ERAT during the blanking period in patients undergoing PFA versus radiofrequency (RF) ablation for atrial fibrillation (AF). METHODS:We prospectively enrolled patients undergoing first-time PVI between 2022 and 2025 at our institution. Propensity score matching was performed to address baseline imbalances and group size differences between RF and PFA PVI. The incidence of ERAT and its association with 9-month arrhythmia recurrence, defined as late recurrence of atrial tachyarrhythmias (LRAT), were analyzed. RESULTS:A total of 962 patients were included (420 RF, 542 PFA). Patients with ERAT were more likely to be older, have persistent AF, higher CHA2DS2-VASc scores, larger atria, reduced ejection fraction, and no prior antiarrhythmic drug use. After multivariable adjustment, PFA was independently associated with a lower risk of ERAT compared with RF (hazard ratio [HR] 0.61; 95% confidence interval 0.42-0.88). ERAT was strongly associated with LRAT, with a 3-4-fold higher risk of atrial arrhythmias at 9 months (early ERAT: HR 3.78, P < .001; late ERAT: HR 4.10, P = .001), regardless of ablation modality. CONCLUSION:PFA is associated with a significantly lower risk of ERAT compared with RF ablation. The occurrence of ERAT, irrespective of energy source, predicts a substantially higher risk of LRAT.

Timing for anticoagulation (AC) initiation in atrial fibrillation (AF) after ischemic stroke (IS) remains uncertain. Previous large studies mostly represented high-income countries, with limited representation of severe stroke and low rates of primary outcomes. We aimed to compare AC initiation at different timeframes in a broader and more diverse population. We searched Medline, Embase, Cochrane, and Clinical Trials for trials and observational studies comparing early versus late AC initiation in AF after IS. The study groups were 0–4, 5–14, and ≥ 15 days. Primary endpoints were recurrent IS only and intracranial hemorrhage (ICH). Secondary endpoints included systemic embolism, all-cause mortality, and major bleeding. Sensitivity analysis focused on studies using direct oral anticoagulants and timing categories consistent with our classification. Our meta-analysis included 20 studies with 25,884 patients. Mean NIHSS was 6.14, with at least 3204 severe strokes. IS was similar between groups, but the 0–4 days strategy ranked first (P-score = 0.92). Sensitivity analysis showed reduced recurrent IS in the 0–4 days group versus the ≥ 15 days group (RR, 0.28; 95

INTRODUCTION:Use of high-frequency low-tidal volume (HFLTV) and high-frequency jet ventilation (HFJV) during pulmonary vein isolation (PVI) improves acute procedural success and long-term outcomes compared to conventional ventilation. However, the impact of HFLTV compared to HFJV on acute and long-term outcomes is unknown. METHODS:We prospectively identified 1039 patients who underwent first-time PVI or PVI with posterior wall isolation (PWI) at our institution between 2022 and 2024 with HFLTV or HFJV. Acute procedural and safety outcomes were analyzed. Twelve-month arrhythmia-free survival was evaluated using the Kaplan-Meier and Cox proportional hazards method. RESULTS:After excluding 44 patients who required discontinuation of HFJV, 860 patients receiving HFJV were compared with 179 receiving HFLTV ventilation. Mean age was 65 years, 93% were White, 30% female and 53% had paroxysmal AF. First-pass isolation (FPI) rates were similar between ventilation strategies. HFLTV was associated with a higher rate of intraprocedural hypotension (31% vs 23%, p = 0.02). Complications were generally minor and comparable between groups. Arrhythmia recurrence rates at 12 months were similar (HR: 0.89, p = 0.55). There was a trend toward improved outcomes when FPI was achieved for both pulmonary veins in either group. CONCLUSION:In this observational cohort, no significant differences in acute procedural outcomes, safety outcomes, or long-term arrhythmia recurrence were observed between HFLTV and HFJV. Given the specialized equipment and operator training required for HFJV and its non-negligible rate of discontinuation, HFLTV may offer a modest practical advantage in routine clinical practice.

Conduction System Pacing (CSP), particularly Left Bundle Branch Area Pacing (LBBAP), has emerged as a physiological alternative to conventional ventricular pacing. However, optimal lead placement remains challenging. In this study, we investigated whether intraprocedural transesophageal echocardiography (TEE) can facilitate LBBAP implantation and improve procedural efficiency, lead positioning, and electrical outcomes compared with the conventional fluoroscopy-guided approach. In this single-center, retrospective, non-randomized cohort study, we evaluated 405 consecutive patients undergoing LBBAP between January 2018 and March 2025. The study compared a conventional fluoroscopy-only approach in the initial 198 patients and a TEE-guided approach in the subsequent 207 patients. Primary endpoints were categorized as measures of procedural efficiency assessed by total procedure time and fluoroscopy time and electrical performance evaluated by post-procedural QRS duration, R-wave peak time in lead V6, and final lead impedance. The TEE-guided group demonstrated significantly shorter total procedure and fluoroscopy times (65.5 ± 25.2 vs. 89.9 ± 37.9 min; p < 0.001/ 12.8 ± 9.9 vs. 15.8 ± 10.5 min; p < 0.001). Post-procedural QRS duration was narrower in the TEE group (108 ± 16 vs. 116 ± 15 ms; p < 0.001), with a more pronounced reduction in patients with baseline wide QRS (> 140 ms) (ΔQRS: −54 ± 23 vs. −46 ± 21 ms; p < 0.001). Notably, lead impedance was significantly lower with TEE guidance (523.6 ± 115.6 vs. 611.3 ± 155.9 Ω; p < 0.001), while pacing thresholds and R-wave amplitudes were similar. Complication rates were low and comparable. TEE-guided LBBAP implantation is associated with enhanced procedural efficiency and adequate cardiac electrical resynchronization. Incorporation of TEE into CSP implantation protocols warrants further evaluation in randomized trials. Transesophageal echocardiography versus fluoroscopy-guided left bundle branch pacing for pacemaker implant. Representative fluoroscopic and TEE images illustrate left bundle branch pacing with conventional fluoroscopy-only versus adjunctive TEE guidance. TEE allows direct visualization of the interventricular septum and electrode tip, facilitating accurate lead positioning. Quantitative comparisons demonstrate that TEE-guided implantation was associated with significantly shorter fluoroscopy time, comparable or reduced procedure duration, and improved electrical outcomes, including narrower QRS duration and shorter V6 R-wave peak time. RA = right atrium; RV = right ventricle; LA = left atrium; LV = left ventricle; MV = mitral valve; MS = membranous septum; IVS = interventricular septum; TEE = transesophageal echocardiography; LBBP = left bundle branch pacing; RWPT = R-wave peak time

Background:Sex differences in atrial fibrillation (AF) treatment remain unexplored in low- and middle-income settings. Women are less often referred for catheter ablation for AF, and whether procedural efficacy and safety differ by sex remains unclear in this population. Objective:The purpose of this study was to evaluate sex-based differences in baseline characteristics and clinical outcomes among patients with AF who underwent first-time radiofrequency catheter ablation in the Southern Brazilian Registry of Atrial Fibrillation (SBR-AF), a Latin American multicenter prospective registry with ≥12 months of follow-up. Methods:The primary end point was any atrial tachyarrhythmia recurrence. Safety outcomes included periprocedural complications through hospital discharge. Results:In our cohort of 1130 patients, 315 (27.9%) were women. Women were older, were more symptomatic, and had higher thromboembolic risk scores at the time of ablation. Paroxysmal AF was more common in women (82.2% vs 72.3%), whereas persistent AF predominated among men. Over a median follow-up of 1.4 years (interquartile range 1.0-3.6 years), atrial tachyarrhythmia recurrence occurred in 23.5% of women and 19.5% of men (log-rank, P = .14). In paroxysmal AF, men demonstrated greater freedom from recurrence (hazard ratio 0.74; 95% confidence interval 0.51-0.99), whereas outcomes were similar in persistent AF. In men, persistent AF and greater symptom burden independently predicted recurrence; no independent predictors emerged among women. The overall complication rate was 4.2%, with similar safety profiles between sexes. Conclusion:In the largest, real-world, multicenter, prospective cohort of AF ablation in Latin America, women underwent ablation at older ages with greater symptom burden yet achieved efficacy and safety comparable to men.

BACKGROUND:Anti-tachycardia pacing (ATP) that entrains but fails to terminate ventricular tachycardia (VT) provides an opportunity to use post-pacing interval minus tachycardia cycle length (PPI - TCL) as a diagnostic tool. We evaluated whether PPI - TCL from failed ATP could predict the presence of epicardial re-entrant VT circuits in patients with ischemic cardiomyopathies (ICM) vs. non-ischemic cardiomyopathies (NICM). METHODS:A retrospective analysis was conducted of 51 patients who underwent VT ablation at Beth Israel Deaconess Medical Center from January 2020 to March 2025 and had failed ATP episodes recorded by their implantable cardioverter-defibrillators (ICDs). PPI - TCL measurements and critical VT circuit locations (apex, septum, free wall, epicardial) were independently adjudicated. PPI - TCL was stratified by VT location and cardiomyopathy type, with sensitivity analyses for normalized PPI - TCL [(PPI - TCL)/TCL]. RESULTS:Included patients had a median age of 70 years, a median LVEF of 31%, 31 (61%) were infarct cardiomyopathy (ICM) and 20 (39%) were non-infarct cardiomyopathies (NICM). ATP-PPI was significantly longer at locations further from the ICD pacing electrode (i.e: free wall, epicardial) as compared to locations that were closer (i.e: apex, septum) (p = 0.023). This relationship held true for NICM (p = 0.026) but not for ICM (p = 0.085). For patients with non-infarct cardiomyopathies, an optimal ATP-PPI cutoff of 165 ms provided an 86% sensitivity and 77% specificity for predicting epicardial circuits. CONCLUSION:PPI - TCL following failed ATP reliably predicts epicardial VT circuits in NICM with a 165 ms cutoff offering high sensitivity and specificity. This non-invasive tool may guide epicardial access planning in NICM VT ablation, though prospective validation is needed.

QuestionIs conduction system pacing (CSP) noninferior to biventricular pacing (BiVP) for patients with heart failure with reduced ejection fraction (HFrEF) and left bundle-branch block (LBBB)?FindingsIn this randomized clinical trial of 173 patients across 14 sites in Brazil, CSP was inferior to BiVP for a hierarchical composite of all-cause death, heart failure hospitalizations, urgent heart failure visits, and change in left ventricular ejection fraction at 12 months.MeaningThese findings do not support the routine use of CSP as the first-line cardiac resynchronization strategy in patients with HFrEF and LBBB. ImportanceConduction system pacing (CSP) is a promising and potentially cost-effective alternative to biventricular pacing (BiVP) in patients with heart failure with reduced ejection fraction (HFrEF) and left bundle-branch block (LBBB), but its impact on heart failure (HF) outcomes remains uncertain.ObjectiveTo compare CSP vs BiVP on an HF-related outcome in patients with HFrEF and LBBB.Design, Setting, and ParticipantsPhysioSync-HF (Conduction System Pacing Versus Biventricular Resynchronization in Patients With Chronic Heart Failure) was an investigator-initiated, multicenter, noninferiority randomized clinical trial enrolling participants from November 2022 to December 2023 with 12 months of follow-up at 14 hospitals across all regions of Brazil. Adults with symptomatic HFrEF (New York Heart Association NYHA] classes II through III), left ventricular ejection fraction (LVEF) of 35% or less, and LBBB (QRS duration >= 130 milliseconds) were eligible for inclusion. Data were analyzed from May to August 2025.InterventionPatients were randomized 1:1 to either CSP (preferentially left bundle-branch area pacing) or BiVP.Main Outcomes and MeasuresThe primary outcome was a hierarchical composite of death, HF hospitalizations, urgent HF visits, and change in LVEF at 12 months. The prespecified noninferiority margin for the odds ratio (OR) was 1.2.ResultsA total of 173 patients (median [IQR] age, 62 years [56-68]; 86 female patients [49.7%]; 115 (66.5%) with dilated cardiomyopathy; median [IQR] LVEF, 26% [22%-31%]; median [IQR] QRS, 180 milliseconds [170-200]) were included. At 12 months, CSP failed to meet noninferiority and was inferior to BiVP for the primary end point (OR, 2.36; 95% CI, 1.37-4.06; P = .99 for noninferiority; P = .002 for between-group difference). The time-to-event composite of death, HF hospitalizations, or urgent HF visits was higher in CSP (hazard ratio, 2.35; 95% CI, 0.99-5.61). Mean (SD) LVEF increased to 35% (12%) with CSP and 39% (12%) with BiVP (mean difference, 3.8%; 95% CI, 0.3%-7.3%). Relative to baseline, both groups had comparable improvements in QRS duration, Kansas City Cardiomyopathy Questionnaire Overall Summary Score, NYHA class, and natriuretic peptide levels. Total direct medical cost related to the procedure and heart failure care was the equivalent of $7090 (95% CI, $5779-$8648) lower in patients randomized to CSP at 12 months.Conclusions and RelevanceIn patients with HFrEF and LBBB, CSP was inferior to BiVP for a composite of death, HF hospitalizations, urgent HF visits, and change in LVEF at 12 months. These findings do not support the routine use of CSP as the first-line resynchronization strategy in this population.Trial RegistrationClinicalTrials.gov Identifier: NCT05572736 The PhysioSync-HF randomized clinical trial compares conduction system pacing vs biventricular pacing on heart failure-related outcomes in patients with heart failure with reduced ejection fraction and left bundle-branch block.